The present invention pertains to a new and improved inflatable game ball, and to a method of repressurizing balls, such as tennis balls, which have lost some or all of their internal air pressure and become dead.
Certain types of game balls, exemplified by tennis balls and racket balls, are made with relatively thin rubber shells which are inflated by air pressure to several pounds per square inch, which gives them a lively bounce and action that makes for a fast game. However, air leaks slowly through the rubber, and in time the ball will become almost totally deflated. In most cases, air leakage is by diffusion through the molecular spaces in the rubber, and the amount of leakage is primarily a function of the time that has elapsed since the pressurized can that the ball was shipped in was opened. Thus, a brand new tennis ball or racket ball that has been used only once or twice and then set aside for a few weeks may be considerably softer, and somewhat dead, when used again in play. Tennis balls are fairly expensive, and the cost becomes an objectionable item when a item when a ball goes dead after being used only a few times.
Another item is that brand new tennis balls rarely have the exact same bounce. Sometimes, a brand new ball will have so little bounce that it cannot be used at all. Bounce is determined by dropping the balls from a given height. Ideally, all brand new balls dropped from a given height should bounce up to the same level, but this is seldom the case. As a result, when players use one ball after another, the action of the ball becomes unpredictable, and players have difficulty in controlling their shots.